A 16-year-old boy from California hopped a fence at the San Jose, Calif., Airport and sneaked into the wheel well of a Hawaiian Airlines jetliner, stowing away for a five-hour flight, FBI spokesman Tom Simon told ABC News.

Simon said the boy, who had run away from home, passed out inside the unprotected, unpressurized wheel well after the flight was airborne. When the plane landed at Maui Airport at 10:30 a.m. Sunday, the boy was still passed out, Simon said. He did not come to for about an hour.

Ground crews later saw the boy walking around the tarmac, Simon said. He was taken into custody and checked by a doctor and found to have no injuries.

News of the incident was met with suspicion and scrutiny. Most wheel-well stowaways don't survive, falling victim to frigid temperatures and lack of oxygen. The chances of survival of a wheel-well stowaway on a commercial aircraft are about 24 percent, according to the Federal Aviation Administration's Civil Aerospace Medical Institute.

ABC News aviation consultant John Nance is skeptical that the teen could have survived the 2,300-mile flight in the wheel well without an oxygen source.

“I just don’t believe it,” Nance said.

Dr. Richard Besser, ABC News’ chief health and medical editor, said in order to survive inside a wheel well during a flight, the body has to fall into a hibernation-like state, with the heart only beating a couple times a minute.

“It’s near impossible, almost miraculous, and maybe there’s more to the story,” Besser said.

Alison Croyle, a spokeswoman for Hawaiian Airlines, released a statement, writing, "Our primary concern now is for the well-being of the boy, who is exceptionally lucky to have survived."

The boy has not been charged with any federal crimes in Hawaii, Simon said. He has been turned over to Hawaiian child protective services.